The applicant's co-pending International application PCT/GB2004/000138 discloses a system for the storage and deployment of wireline conveyed well intervention tooling using a subsea intervention device. The number of such tool storage systems have been disclosed such as in the applicant's above-mentioned PCT application, or in PCT application number PCT/US01/23518, but neither are optimized for storing and deploying wireline, or coil tubing in the case of PCT/US01/23518 tools using an autonomous, remote system. The aforementioned systems have some disadvantages. Firstly, in the case of PCT/GB2004/000138, it may not be possible to deploy longer rigid tools because of the geometry of getting the tool from the angled pocket into the well centre-line where it has to be made up in the vertical plane, while a portion of the tool remains in the angled pocket. In the case of PCT/US01/23518, the eccentric (i.e. to the wellbore centre-line) carousel system results in a badly balanced system when installing it onto a subsea Christmas tree using an ROV assistance, especially given the wall thickness needed for the carousel to withstand internal oil pressure.